gistfile1.rb

class Hoge
  def self.hoge
    obj = Kernel.const_get(klass.capitalize).new
    attributes.each do |key|
      obj.send("#{key}=", key.to_s + "!!!")
    end
    p obj
  end

  def self.klass
  end

  def self.attributes
  end
end
 
Foo = Class.new(Hoge) do
  attr_accessor :name, :email

  def self.klass
    self.name
  end

  def self.attributes
    [:name, :email]
  end
end

Bar = Class.new(Hoge) do
   attr_accessor :id, :pass

   def self.klass
     self.name
   end

   def self.attributes
     [:id, :pass]
   end
 end

Foo.hoge
Bar.hoge

# % ruby sample.rb
# #<Foo:0x007f871190b858 @name="name!!!", @email="email!!!">
# #<Bar:0x007f871190b498 @id="id!!!", @pass="pass!!!">